This invention relates to the spinning of synthetic polymeric yarns. In a specific embodiment, the invention relates to spinning poly(trimethylene terephthalate) into yarn suitable for carpets.
Polyesters prepared by condensation polymerization of the reaction product of a diol with a dicarboxylic acid can be spun into yarn suitable for carpet fabric. U.S. Pat. No. 3,998,042 describes a process for preparing polytethylene terephthalate) yarn in which the extruded fiber is drawn at high temperature (160.degree. C.) with a steam jet assist, or at a lower temperature (95.degree. C.) with a hot water assist. Poly(ethylene terephthalate) can be spun into bulk continuous filament (BCF) yarn in a two-stage drawing process in which the first stage draw is at a significantly higher draw ratio than the second stage draw. U.S. Pat. No. 4,877,572 describes a process for preparing poly(butylene terephthalate) BCF yarn in which the extruded fiber is drawn in one stage, the feed roller being heated to a temperature 30.degree. C. above or below the Tg of the polymer and the draw roller being at least 100.degree. C. higher than the feed roll. The application of conventional polyester spinning processes to prepare poly(trimethylene terephthalate) BCF results in yarn which is of low quality and poor consistency. It would be desirable to have a process for preparing high-quality BCF carpet yarn from poly(trimethylene terephthalate).
It is therefore an object of the invention to provide a process for preparing high-quality bulk continuous filament yarn from poly(trimethylene terephthalate).